Electrical compensation via vacancy–donor complexes in arsenic-implanted and laser-annealed germanium

Abstract

Room-temperature vacancy migration in crystalline Si from an ion-implanted surface layer

Low temperature deactivation of Ge heavily n-type doped by ion implantation and laser thermal annealing

“…A remarkably high electrically active concentration of 1 Â 10 20 cm À3 is also reached, which corresponds to approximately 50% of the total As concentration, as shown by Figure 1(b). The partial electrical activation after LTA is due to very small As-V clusters, as observed by positron annihilation spectroscopy measurements, 21 most of them containing less than 5 As atoms, formed during the cooling transient of the LTA process. 17 The positive strain reported in Figure 1(c) is due to both As atoms in substitutional, electrically active, configurations (As s ) and As atoms in clusters (As cl ), with lattice volume modification per atom of DV As_s ¼ þ8.8 Å 3 and DV As_cl ¼ þ2.0 Å 3 , respectively.…”

“…23 We speculate that the As deactivation is driven by V point defects, thermally generated and/ or residual from the LTA process, which interact with substitutional As. The resulting AsV mobile species is then trapped by As-V clusters already nucleated after LTA 21 and, at the same time, reaching a clustered, inactive site altering the configuration of the existing clusters. This scenario is consistent with Density Functional Theory (DFT) calculations that report an unfavorable As-As binding energy in Ge, which becomes more stable if mediated by interaction with vacancies.…”

Source/Drain Materials for Ge nMOS Devices

“…Typically, lower intensities are observed in the peak region for the larger open-volume defects. 50 The positron annihilation at high momenta (p > 1.5 a.u.) is mainly dominated by the positron annihilating with the 3d core electrons of Ge.…”

Quantitative scanning spreading resistance microscopy on n-type dopant diffusion profiles in germanium and the origin of dopant deactivation

“…What both SIMS and APT have in common is that they detect the total, chemical dopant concentration, i.e., no information about the amount of charge carriers, which affect the device performance, is accessible. In cases where dopants are considered to become deactivated, i.e., for highly n-type doped germanium (Ge), [7][8][9] SIMS and APT cannot provide direct evidence about the electrically active dopant concentration. For many years now, spreading resistance profiling (SRP) is a suitable technique to measure charge carrier concentrations.…”

“…9,11,20 A deactivation of dopants can occur in the course of thermal treatments after implantation 9,28 and thermal diffusion of dopants. 8,29 In this work, arsenic and antimony dopant diffusion profiles in undoped and carbon doped Ge, respectively, earlier investigated mainly by SIMS, 29 are additionally analysed with SSRM. A cross-sectional preparation, completed with a chemical-mechanical-polishing step, is applied to all samples for the SSRM analysis.…”